Rabdosia rubescens (Hemls.) Hara (family Labiatae of Isodon), also named Donglingcao in traditional Chinese medicine, contains abounding diterpenoid ingredients. There have been more than 500 kinds of diterpenoids separated from that kind of plant by now, among which many of those having ent-kaurene structure have activities including antibacterial activity, cytotoxic activity, anti-tumor activity, activity in inhibiting the mitochondrial oxidative phosphorylation, insect-antifeeding activity, plant growth regulation activity anti-inflammatory activity, regulation of cardiovascular functions, etc. . . . (S Ttanaba and HNishikawa, JpnJBact, 1954(9), 475; M Yamaguchi, M Taniguchi, I Kubo and T Kubota, Agr Biol Chem, 1977(41), 2475; T Arai, Y Koyama, T Suenaga and T Morita, Chemotherapy, 1962(10), 197; M Taniguchi, M Yamaguchi, I Kubo and T Kubota, Agr Bioi Chem, 1979(43), 71; Li Qi, Chen Zheng, Liu Jie, Sun Handong, Lin Zhongwen, Chinese Pharmacological Bulletin, 1992, 8(1), 3; Li Huilan, Wang Maode, Zhang Zhaojiu, Chinese Drugs Bulletin, 1988, 18(10), 46) As a result, it is valuable in theory and in practice to research those plants, especially an ent-kaurene diterpenoid which has an excellent anti-tumor activity.
The structure of ent-kaurene diterpenoid having an α-exomethylene cyclopentanone unit is represented as follows:

The α-exomethylene cyclopentanone unit in that structure has been determined as the anti-tumor active center of those substances after research. (S Ttanaba and H Nishikawa, Jpn J Bact, 1954 (9), 475; T Arai, YKoyama, T Suenaga and T Morita, J Antibiotics Ser, 1963, A16, 132; I Kubo, M Taniguchi, Y Satomura and T Kubota, Agr Biol Chem, 1974(38), 1261; T Arai, Y Koyama, T Morita and H Kaji, Chemotherapy, 1961(9), 403; I Kubo, M Taniguchi and T Kubota, Rev Latinoamer Quim, 1978(9), 157) Oridonin A is the representative of those having such structure. There are many researches now on oridonin A. Zhang Tanmu researching group from Henan Medical University and Fujita researching group from Japan etc. have all done much pharmacological research on oridonin A. It is assuredly proven that oridonin A has antitumor activity both in vitro and in vivo. It also has a broad antitumor spectra and can effectively kill cells including human nasopharyngeal carcinoma cell, human hepatoma cell, human cervical carcinoma cell, esophageal carcinoma cell etc. . . . . However, due to oridonin A having low stability and water-solubility and difficulty in controlling the quality of oridonin A's extration solution, the development of oridonin A is confined to the extent. We have synthesized a series of glucoside and ester compounds (ZL99101179.3). It has high practical value and meaning in developing the traditional Chinese herbal medicine R. rubescens (Donglingcao) to develop a new pharmaceutical compound by using diterpenoid ingredient from R. rubescens with a high content and a good anti-tumor activity based on those former research works. We synthesized and found more derivatives having higher anti-tumor activity, less toxicity and better property without destroying its active center structure.